Situational awareness was working against both pilots. No apparent communication or tower. focus is landmark forward if this is near a landing strip. From slightly above and behind the B17, banking to over 30 degrees left, can't see thru the bottom of the craft. Possible blind side accident. Pilot error. If intentional, without guidance, that would have been a skilled pilot. My dogleg blindside two cents... is saddened for the casualties no matter.